Modular rig mat

ABSTRACT

A modular rig mat is formed from a core panel have a plurality of edges, and a perimeter frame surrounding the core panel comprising a plurality of frame rails having a transverse profile for engaging corresponding edges of the core panel and a plurality of corner components adapted to connect between adjacent frame rails.

FIELD OF THE INVENTION

The present invention relates to a modular rig mat and methods of assembling a modular rig mat.

BACKGROUND

In the oil and gas industry, ground cover mats or rig mats are used to temporarily support heavy equipment and transport trucks over wet or disturbed ground in remote locations. These mats tend to have a high weight per area and need to cover significant areas. Accordingly, the mats are provided in manageable sizes and weights, transported to remote locations, interlocked together for use, and thereafter disassembled.

There are many prior art configurations of rig mats. A conventional rig mat consists of planking contained within a steel perimeter frame formed from I-beams. The frame is typically welded together at the corners, where the I-beams abut each other at right angles.

SUMMARY OF THE INVENTION

In one aspect, the invention comprises a modular rig mat comprising:

-   -   a. a core panel have a plurality of edges;     -   b. a perimeter frame surrounding the core panel, and comprising         a plurality of frame rails having a transverse profile for         engaging corresponding edges of the core panel and a plurality         of corner components adapted to connect between adjacent frame         rails and defining a pocket for receiving the core panel.

In one embodiment, the core panel may be square or rectangular having two short edges and two long edges. The rig mat may further comprise a connector box adapted to connect between two frame rails disposed end-to-end, which may be a shackle box comprising a shackle. Either or both of the corner components and the shackle box may be cast components, and cast from steel, aluminum, metal alloys, a plastic or polymer, or a composite material. Each long edge may comprise at least two side rails interconnected by a shackle box. The cast components may comprise steel and are welded to the frame rails. Each frame rail transverse profile may be angled or rounded between a top flange and a bottom flange, or may be substantially square. The core panel edge preferably has a profile matching the frame rail transverse profile.

In one embodiment, each corner connector comprises a nesting connector profile having a shape matching the frame rail transverse profile, and each connector box comprises a connector profile having a shape matching the frame rail transverse profile.

In another aspect, the invention may comprise a method of assembling a rig mat having a core panel, comprising the steps of:

-   -   a. assembling a perimeter frame around the core panel, the         perimeter frame comprising a plurality of corner connectors and         a plurality of frame rails, each defining a channel or pocket         for receiving the core panel; and     -   b. fastening the corner connectors and frame rails together.

In one embodiment, the perimeter frame further comprises connector boxes for connecting two end-to-end frame rails. Preferably, the perimeter frame components are welded together, and preferably, the components are welded together with an overlapping joint.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like elements are assigned like reference numerals. The drawings are not necessarily to scale, with the emphasis instead placed upon the principles of the present invention. Additionally, each of the embodiments depicted are but one of a number of possible arrangements utilizing the fundamental concepts of the present invention. The drawings are briefly described as follows:

FIG. 1 shows a perspective view of one embodiment, of an assembled rig mat of the present invention.

FIG. 2 shows the embodiment of FIG. 1 in an exploded view.

FIG. 3 shows a top plan view of the embodiment of FIG. 1.

FIG. 4 shows a side plan view of the embodiment of FIG. 1.

FIG. 5 shows an end plan view of the embodiment of FIG. 1.

FIGS. 6A-C shows perspective and plan views of one embodiment of a corner component.

FIGS. 7A and 7B shows a perspective and side plan view of one embodiment of a shackle box.

FIGS. 8A-E shows alternative transverse cross-sectional profiles of a frame rail.

DETAILED DESCRIPTION

In one aspect, the invention comprises a quadrilateral rig mat (10) having a perimeter frame (12) comprising four corner components (14) connecting frame rails, and a core panel (20) disposed within the perimeter frame (12). The exemplary rig mats illustrated are rectangular, thus entailing at least two short side rails (16) connected between two corner components (14), and at least two long side rails (18) connected between two corner components (14), wherein the corners are right angles. However, square rig mats are also within the scope of the present invention, as well as rig mats of alternative geometries. Each component of the perimeter frame comprises an upper flange and a lower flange, which together define a channel or pocket which receives the core panel.

The core panel (20) may comprise any flat panel which forms a weight-bearing surface of the mat, comprising wood, plastic, metal components or any combination thereof. In one embodiment, the core panel may comprise a contiguous wood panel such as a cross-laminated wood/plastic composite panel. In another embodiment, the core panel may comprise a plurality of elongate members, such as 2×6 or 2×4 lumber, abutted together to form the panel. The core panel may comprise transverse beams or straps which connect or attach to the perimeter frame to provide added strength. The edges and corners of the core panel (20) may be configured or shaped so as to fit within the perimeter frame (12) as described below. Rig mats of the present invention may comprise a single core panel, or multiple core panels fitted together within the perimeter frame. Exemplary core panels have a thickness of about 6″.

The configuration of the core panel is not an essential element of the present invention. The modular nature of the perimeter frame allows adaptation and use with a wide variety of different core panels.

In one embodiment, each corner component (14) comprises two nesting connector profiles (142) for engaging the two frame rails which are joined by the corner component, and a corner pocket (144) for engaging the core panel. Each connector profile (142) has a shape which matches the cross-sectional profile of a frame rail, such that the frame rail overlaps or nests the connector profile (142) when assembled. This overlaps allows the ability to lap joint weld the two components together, as opposed to a simple butt joint.

The corner component (14) may be adapted for lifting or moving by a sling or other means and accordingly may comprise a standard roll end (146), a recessed standard roll end, an intermodal container connection, a shackle, a hook, or a simple opening for lifting attachments, or a combination of these adaptations. The roll end (146) may be configured to be used with a mat interlocking device, such as that described in co-pending Canadian Patent Application No. 2,864,350.

The corner pocket (144) may be formed diagonally to match a diagonal corner of a core panel (20), as is shown in FIG. 2. The corner components (14) may be symmetrical about a diagonal axis (A) such that the length from the end of the roll end (146) to each side profile (142) is substantially the same. Alternatively, the corner component may be elongated in one direction, such that the length from the end of the roll end (146) is longer to one side connector profile (142) than to the other side connector profile (142).

In one embodiment, the corner components (14) are cast components. As used herein, a “cast” component is one that is made from a casting process, whereby a liquid material is poured into a mold and allowed to solidify, taking the shape of the mold. Casting processes are well known in the art. In one embodiment, the cast components of the present invention will comprise a metal such as steel or alloys, however, other castable materials with sufficient physical strength (tensile and compressive) may be used, such as various plastics or polymers.

Each frame rail, whether short side or long side, is an elongate channel member having an upper flange (162) and a lower flange (164), which form a cross-sectional profile shape defining the channel (166). The cross-sectional profile may be a simple square side profile (FIG. 8E), or various angled or rounded profiles (FIGS. 8A-D). In each case, the channel (166) receives and wraps around the edge of the core panel (20), and acts to protect the edges of the core panel from impacts and loads. The thickness of the frame rail and the width of the flanges are chosen to provide adequate stiffness and strength to the perimeter frame, having regard to the material chosen and the configuration of the core panel. The frame rails may be steel, aluminum, a metal alloy, a plastic or polymer, a composite material, or some other suitable structural material. In one embodiment, the side edges of the core panel are beveled or rounded to closely fit a frame rail cross-sectional profile, as is shown in FIG. 8B.

Each of the angled or rounded profiles has the advantage of permitting fork lift tines to insert between vertically stacked mats.

In one embodiment, the perimeter frame may further comprise a plurality of connector boxes (22) which connect between two frame rails placed end-to-end, and may each comprise opposing connector profiles (222) for engaging a frame rail and a channel (224) for receiving and engaging the core panel. In one embodiment, the connector boxes are preferably shackle boxes (22) which comprise a shackle. The shackle box preferably comprises a cast component.

The shackle boxes (22) may each comprise a standard shackle (226) which is rotatably connected to a shackle lug (228) with a bolted pin (230), and which rests within a recessed pocket when laying horizontal. The recessed pocket may have a drain hole (232) to prevent water accumulation. In one embodiment, the shackle is also positioned so that it does not rest on the bottom of the recess, in fact it is substantially level with the surface of the shackle box, which minimizes the chance it will embed in ice or debris which may form at the bottom of the recess.

A locking box (not shown) may also be provided, particularly along the long side of the perimeter frame, to provide a feature which allows interlocking between adjacent rig mats using an interlocking device. An exemplary lock box would be similarly configured to a connector box (22), allowing interconnection between end-to-end frame rails.

The rig mat of the present invention may be assembled in different dimensions due to the modular nature of the perimeter frame components. In its most basic version, four frame rails (16) may be connected between four corner components, to form a perimeter frame about a core panel, which may be square or rectangular. If the rails and corner components are made from steel, then the rails and corners may be welded together in conventional fashion. In alternative embodiments, the frame rails and corner components may be connected with adhesives, riveted or bolted together, or some other suitable method of connection.

In a preferred embodiment, frame rails may be provided in different standard lengths and assembled to form a rig mat of a desired size. For example, if frame rails are supplied in 6 foot, 10 foot and 20 foot lengths, rig mats which are approximately 20′×8′, or 30′×8′, or 40′ feet×8′ may be assembled by placing the 6 foot lengths as short side rails, and choosing or interconnecting the 10 and 20 foot lengths with shackle boxes to form the long side of the perimeter frame.

An exploded view of one embodiment of a modular rig mat is shown in FIG. 2, which illustrates the connections between the perimeter frame components, and the engagement of the core panel (20). As may be seen, each corner components has a connector profile which closely matches the frame rail transverse profile. As well, each shackle box has opposing profiles which closely match the frame rail transverse profile. As shown in the Figures, the frame rails may install by overlapping over top or outside of the corner component profile (142) and shackle box profiles (222). Alternatively, that overlap may be reversed.

In one embodiment, tie rods (30) may be inserted through the core panel between opposing frame rails or shackle boxes and fastened with threaded fasteners, to provide a compressive force between the opposing long sides of the perimeter frame.

As shown in FIG. 2, the core panel may be notched where it fits into each shackle box, to accommodate the recessed pocket which holds the shackle, and which impinges on the channel (224) which receives the core panel.

Definitions and Interpretation

The singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for the use of exclusive terminology, such as “solely,” “only,” and the like, in connection with the recitation of claim elements or use of a “negative” limitation. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.

The term “and/or” means any one of the items, any combination of the items, or all of the items with which this term is associated. The phrase “one or more” is readily understood by one of skill in the art, particularly when read in context of its usage.

As will also be understood by one skilled in the art, all language such as “up to”, “at least”, “greater than”, “less than”, “more than”, “or more”, and the like, include the number recited and such terms refer to ranges that can be subsequently broken down into sub-ranges as discussed above. In the same manner, all ratios recited herein also include all sub-ratios falling within the broader ratio.

One skilled in the art will also readily recognize that where members are grouped together in a common manner, such as in a Markush group, the invention encompasses not only the entire group listed as a whole, but each member of the group individually and all possible subgroups of the main group. Additionally, for all purposes, the invention encompasses not only the main group, but also the main group absent one or more of the group members. The invention therefore envisages the explicit exclusion of any one or more of members of a recited group. Accordingly, provisos may apply to any of the disclosed categories or embodiments whereby any one or more of the recited elements, species, or embodiments, may be excluded from such categories or embodiments, for example, as used in an explicit negative limitation.

As will be apparent to those skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the scope of the invention claimed herein. The various features and elements of the invention described herein may be combined in a manner different than the specific examples described or claimed herein without departing from the scope of the invention. In other words, any element or feature may be combined with any other element or feature in different embodiments, unless there is an obvious or inherent incompatibility between the two, or it is specifically excluded. 

1. A modular rig mat comprising: a. a core panel have a plurality of edges; b. a perimeter frame surrounding the core panel, and comprising a plurality of frame rails having a transverse profile for engaging corresponding edges of the core panel and a plurality of corner components adapted to connect between adjacent frame rails and defining a pocket for receiving the core panel.
 2. The rig mat of claim 1 wherein the core panel is square or rectangular having two short edges and two long edges.
 3. The rig mat of claim 2 further comprising a connector box adapted to connect between two frame rails disposed end-to-end.
 4. The rig mat of claim 2 wherein the connector box is a shackle box comprising a shackle.
 5. The rig mat of any claim 3 wherein either or both of the corner components and the shackle box are cast components.
 6. The rig mat of claim 5 wherein the cast components comprise steel, aluminum, metal alloys, a plastic or polymer, or a composite material.
 7. The rig mat of claim 2 wherein each long edge comprises at least two side rails interconnected by a shackle box.
 8. The rig mat of claim 6 wherein the cast components comprise steel and are welded to the frame rails
 9. The rig mat of claim 1 wherein each frame rail transverse profile is angled or rounded between a top flange and a bottom flange.
 10. The rig mat of claim 1 wherein each frame rail transverse profile is substantially square.
 11. The rig mat of claim 8 wherein the core panel edge has a profile matching the frame rail transverse profile.
 12. The rig mat of claim 11 wherein each corner connector comprises a nesting connector profile having a shape matching the frame rail transverse profile.
 13. The rig mat of claim 12 wherein each connector box comprises a connector profile having a shape matching the frame rail transverse profile.
 14. The rig mat of claim 4 wherein the shackle box defines a drain hole.
 15. The rig mat of claim 4 wherein the shackle box is configured such that the shackle does not rest on a bottom of the shackle box.
 16. The rig mat of claim 1 further comprising a tie rod extending between and affixed to opposing frame rails.
 17. The rig mat of claim 3 further comprising a tie rod extending between and affixed to opposing connector boxes.
 18. A method of assembling a rig mat having a core panel, comprising the steps of: a. assembling a perimeter frame around the core panel, the perimeter frame comprising a plurality of corner connectors and a plurality of frame rails, each defining a channel or pocket for receiving and engaging the core panel; and b. fastening the corner connectors and frame rails together.
 19. The method of claim 18 wherein the perimeter frame further comprises connector boxes for connecting two end-to-end frame rails.
 20. The method of claim 19 wherein the perimeter frame components are welded together.
 21. The method of claim 20 wherein the perimeter frame components are welded together with an overlapping joint. 